Ans.
1. With the discovery of new elements, it was found that they did not obey the law of octaves.
2. To fit all the known 56 elements, Newlands placed two elements in the same position. For example, Co and Ni, Ce and La.
3. He placed some elements with different properties under the same note in the octave. For example, he placed metals Co and Ni along with halogens, while Fe having similarity with Co and Ni was placed away along with the nonmetals O and S.
4. Newlands law of octaves was applicable only upto calcium.
